Apparatus for producing flat wood fragments



P. VOELSKOW Vlay 26, 1970 APPARATUS FOR PRODUCING FLAT WOOD FRAGMENTS 2 Sheets-Sheet 1 Filed Nov. 13, 1967 o S mctwm lNVLN/OR. PeTer Voel$ kow BY W United States Patent US. Cl. 144-3 Claims ABSTRACT OF THE DISCLOSURE A cellulosic pulp cooked and saturated with water is continuously fed into a rotating cage comprising a set of rollers which turn about an axis of rotation parallel to their own axes and which entrain the mass outwardly and squeeze it against the inner wall of a stationary and heated cylindrical housing toward which they are centrifugally urged. A set of blades fixedly mounted on the revolving cage between adjoining rollers help drive the pulp axi ally forward toward an end plate rotating with the rollers, this plate having radially extending ribs directing the flattened cellulose fragments into a discharge channel. The rollers are preferably axially subdivided into sections which are independently displaceable in radial direction.

My present invention relates to an apparatus for producing flat wood fragments adapted to be used in the manufacture of sheets or plates of the pressed-board type. Pressed boards are generally classified either as fiberboards or as chipboards, the latter being made from relatively coarse fragments or chips with synthetic-resin bonding whereas the former are obtained from pulpy cellulosic material of the kind known as half stuff. In practice, fiberboard plates can only be made of rather limited thickness so that the sturdier chipboard plates must be utilized for many important commercial applications.

The chips employed in the manufacture of such plates can be produced by comminuting machinery such as disclosed in my prior US. Pat. No. 3,319,673 and my copending application Ser. No. 509,262, filed July 18, 1967. These fragmentation-type chip formers can be operated at high speed and with great efficiency; nevertheless, they require the services of skilled attendants and also need frequent resharpening of their cutting implements.

The general object of my present invention, therefore, is to provide an alternate system for producing flat wood fragments, suitable for incorporation in chipboard plates, which avoids these inconveniences and can be operated with a minimum of supervision for indefinite periods.

A more particular object of my invention is to provide means for producing wood fragments of an intermediate character, coarser than cellulosic fibers but more pliable than the chips obtained from conventional comminuting equipment, which can be worked into boards or sheets that do not require any special polishing or surface coating to eliminate the rough spots so often encountered in the production of chipboard plates by the known processes.

I have found, in accordance with the present invention, that these objects can be realized by means of an apparatus which utilizes the pressure of one or more rollers urged centrifugally against a generally cylindrical housing wall to flatten the at least partly coherent particles of a pulpy cellulosic mass which, advantageously, is taken directly from a cooking vessel wherein chips, slivers and/ or chunks of wood are saturated with water and heated to high temperatures, preferably at substantially atmos- 3,513,890! Patented May 26, 1970 pheric pressure. In order to maintain the elevated temperature of the mass during its compression between the rollers and the housing, the latter is advantageously heated separately to a suitable operating temperature above the boiling point of water, e.g. between and C.

With the housing held stationary, the rollers are arranged to revolve about the housing axis by being mounted on a rotatable cage with the aid of individual supporting rods extending parallel to the axis of rotation, preferably horizontally. In principle, the necessary centrifugal pressure can be generated by allowing a certain radial play to either the supporting rods on the rotating cage structure or the rollers on their respective rods. In practice, in order to insure an adequate and reasonably uniform degree of compression, I prefer to make the rods rigid with the cage and to subdivide each roller axially into a plurality of sections which are independently movable with reference to the rods, within certain limits, in radial direction.

In accordance with another important feature of my invention I provide, within the narrow gap between at least one pair of adjoining rollers which are rotatively entrained in a planetary motion by the relative rotation between the supporting cage and the housing wall, one or more vanes which are stationary on the roller support and which are so shaped as to impart to the outwardly moving mass an axial velocity component toward the housing outlet. Thus, the vanes may have a twisted shape similar to that of propeller blades and may be adjustable in pitch and/or inclination, preferably during operation of the machine, to vary the rate of discharge of the mass of compacted fragments from the housing. Such discharge may be facilitated by means of an end plate confronting the interior of the housing which is open toward the plate, the latter rotating with the roller-supported structure about the housing axis and being advantageously formed with generally radial ribs helping eject the treated mass with its flaky wood fragments into a surrounding annular channel.

The invention will be described in greater detail with reference to the accompanying drawing in which:

FIG. 1 is a sectional elevational view of an apparatus representing a preferred embodiment;

FIG. 2 is a cross-sectional view taken on the line 11-11 of FIG. 1; and

FIG. 3 is a sectional detail view taken on the line IIIIII of FIG. 2.

The machine shown in the drawing comprises, essentially, a first stage in the form of a cooking vessel 3 and a second stage designed as a centrifugal rolling mill 19. Vessel 3 has a hopper 2 through which pieces of wood 1 are continuously introduced into its interior. A hot and humid atmosphere is maintained in the vessel, as by the admission of superheated steam through a port 21. In this atmosphere the wood chunks or chips are moisturesaturated and softened but still retain a certain degree of cohesiveness. The resulting pulp is continuously propelled toward an outlet 5 by an agitator comprising a set of pitched blades 4 on a shaft 4a, the latter being driven via a transmission 23 from a motor not shown.

Outlet 5 has the form of a downwardly sloping neck which opens generally axially into a short tubular shaft 7 horizontally journaled in bearings 6 on the base of the centrifugal mill 19. Shaft 7 has a radial flange 12 to which are secured a set of horizontal rods 11 extending parallel 'to the axis of rotation O of the shaft. The other ends of rods 11 are anchored to a disk-shaped end plate 13 fixed to a shaft 14 which is journaled in bearings 15 centered on axis 0 and is driven by a motor (not shown) through a transmission 14. Plate 13 and flange 12 are further interconnected by a set of tubular bars 18 interspersed 3 with rods 11; thus, the structure 7, 11, 13, 14, 18 forms a cage rotatable about the horizontal axis 0.

Each of the rods 11 loosely passes through a respective roller 9 of cylindrical shape disposed close to the inner peripheral wall of a stationary cylindrical housing 8 surrounding the cage, this housing being rigid with the base of mill 19 and being open toward the plate 13, i.e. toward the left as viewed in FIG. 1. An extension 22 of the mill base defines, together with a partition 22', an annular channel which surrounds the disk 13 and a confronting flange 8 of housing 8, the disk and the flange defining between them a gap for the discharge of the mass admitted by way of inlet shaft 7. Channel 20, in turn, is provide with an exit 25 for the treated material.

Within the narrow gaps between adjacent rollers 9 there are mounted a set of vanes 17 which are carried by the bars 18 so as to be a fixed part of the rotating cage structure referred to above. The vanes 17 have the shape of propeller blades and are so arranged as to impart a forward (i.e. leftward in FIG. 1) component of motion to the mass moving radially outwardly between the rollers 9, particularly in the vicinity of that roller of each pair whose peripheral velocity is directed outwardly along the gap. Thus, as the disk 13 and the remainder of the cage rotate about the axis 0 in the direction of arrow A (FIG. 2), i.e. counterclockwise, the rollers 9 are urged radially outwardly by the centrifugal force into direct or indirect contact with the inner periphery of housing 8 so as to rotate in the direction of arrows B, i.e. clockwise as viewed in FIG. 2. The cellulosic mass, subject to the same centrifugal force and to outward frictional entrainment by one of the two rollers flanking each gap, tends to follow that roller and to become crushed between it and the housing 8. During this movement the mass is forwardly deflected by the adjacent edge of the nearest vane 17, this process being repeated as individual wood fragments move along generally wavy paths P with reference to the roller array until they finally reach the open end of housing 8. At this point they are seized by a group of radial ribs 16 on the rotating disk 13 which centrifugally eject them into the discharge channel 20 for ultimate removal from the apparatus.

In order to facilitate the crushing and flattening of the soaked wood particles between the rollers 9 and the housing 8, I prefer to maintain the housing wall at an elevated temperature (e.g. of 120 to 180 C.) by suitable heating means diagrammatically indicated in FIG. 1 as a coil 26 for the passage of a hot fluid. This treatment converts the blocks or chunks of wood into flake-shaped cellulosic particles which are eminently suitable for the production of pressed boards.

In order to distribute the roller pressure as nearly uniformly as possible and to maintain their effectiveness even upon intrusion of large-size chunks between them and the housing wall, I prefer to subdivide each roller 9 into a plurality of axially adjoining sections 9a, 9b, 9c, 9d which are independently movable in a radial direction.

It is also desirable to provide means for adjusting the pitch of the blades 17 on their respective bars 18 to alter the rate of feed for the purpose of varying the average degree of flattening of the particles, such an adjustment being sometimes necessary even during operation of the machine. To this end, as best seen in FIG. 3, each blade 17 may be swivelably mounted on its carrying bar 18 and may have a splined spur 17 engaged by a rack 27 extending within the bar 18 and terminating in a head 27 biased by a spring 28. Head 27' bears through a ball 29 upon a toothed ring 30 threaded onto a flange 19' of the mill housing; rotation of ring 30 in one direction or the other, by means of a worm 31 in mesh therewith and secured to a crank 32, thus causes a shift in the position of the several racks 27 controlling the associated blades 17. It will be understood that the assembly 2732 is representative of a variety of means (mechanical, electrical, hydraulic etc.) for repositioning the blades 17 during operation.

It will be apparent that, if desired, the vane-carrying bars 18 may be omitted between some of the roller pairs and that other modifications may be made without departing from the spirit and scope of my invention as defined in the appended claims.

I claim:

1. An apparatus for producing flat wood fragments, comprising feed means for supplying a cellulosic watersaturated mass containing partly coherent wood particles; a generally cylindrical housing provided with an axial inlet for receiving said mass from said feed means; support means in said housing rotatable about the housing axis; roller means carried by said support means with freedom of rotation about an eccentric axis parallel to said housing axis near the inner periphery of said housing for frictional entrainment thereby upon relative rotation of said support means and said housing whereby said mass is urged centrifugally outwardly and entrained by said roller means for compression between the latter and said inner periphery; outlet means for discharging the compressed mass from said housing; and drive means for rotating said support meanssaid outlet means incduding an end plate adjacent said housing rotatable in unison with said support means, said housing 'being open toward said end plate and being provided with an extension forming an annular channel around said end plate, said channel communicating with the interior of said housing for receiving said mass therefrom.

2. An apparatus as defined in claim 1 wherein said roller means includes at least two peripheraly spaced rollers separated by a narrow gap, further comprising blade means on said support means shaped to deflect said mass axially toward said outet means.

3. An apparatus as defined in claim 1 wherein said end plate is provided with generally radial ribs facing said housing.

4. An apparatus for producing flat wood fragments, comprising feed means for supplying a cellulosic watersaturated mass containing partly coherent wood particles; a generally cylindrical housing provided with an axial inlet for receiving said mass from said feed means; support means in said housing rotatable about the housing axis; a plurality of peripherally spaced rollers separated by narrow gaps and carried by said support means with freedom of rotation about an eccentric axis parallel to said housing axis near the inner periphery of said housing for frictional entrainment thereby upon relative rotation of said support means and said housing whereby said mass is urged centrifugally outwardly and entrained by said roller means for compression between the latter and said inner periphery; outlet means for discharging the compressed mass from said housing; drive means for rotating said support means; and blade means on said support means disposed in said gaps and shaped to deflect said mass axially toward said outlet means.

5. An apparatus as defined in claim 4, further comprising adjustment means for said blade means operable during rotation of. said support means by said drive means.

6. An apparatus as defined in claim 4 wherein said housing is provided with heating means for maintaining said mass at an elevated temperature during compression thereof by said rollers.

7. An apparatus as defined in claim 4 wherein said feed means comprises a cooking vessel provided with agitator means.

8. An apparatus as defined in claim 7 wherein said housing axis is substantially horizontal, said vessel being disposed alongside said housing at a location remote from said outlet means.

9. An apparatus for producing flat wood fragments, comprising feed means for supplying a cellulosic watersaturated mass containing partly coherent wood particles; a generally cylindrical housing provided with an axial inlet for receiving said mass from said feed means; support means in said housing rotatable about the housing axis; roller means carried by said support means with freedom of rotation about an eccentric axis parallel to said housing axis near the inner periphery of said housing for frictional entrainment thereby upon relative rotation of said support means and said housing whereby said mass is urged centrifugally outwardly and entrained by said roller means for compresion between the latter and said inner periphery; outlet means for discharging the compressed mass from said housing; drive means for rotating said support means; blade means on said support means shaped to deflect said mass axially toward said outlet means; and adjustment means for said blade means operable during rotation of said support means by said drive means.

10. An apparatus for producing flat wood fragments, comprising feed means for supplying a cellulosic watersaturated mass containing partly coherent wood particles; a generally cylindrical housing provided with an axial inlet for receiving said mass from said feed means; sup- 20 port means in said housing including at least one rod parallel to and rotatable about the housing axis; roller means carried by said support means with freedom of rotation about an eccentric axis parallel to said housing axis near the inner periphery of said housing for frictional entrainment thereby upon relative rotation of said support means and said housing whereby said mass tis urged centrifugally outwardly and entrained by said roller means for compression between the latter and said inner periphery, said roller means including at least one roller journaled on said rod with limited radial mobility and axially subdivided into a plurality of sections independently movable on said rod in radial direction; outlet means for discharging the compressed mass from said housing; and drive means for rotating said support means.

References Cited UNITED STATES PATENTS 554,802 2/1896 Thomson 241106 2,204,140 6/1940 Langbein 241105 2,212,662 8/1940 Hennessy 241106 2,476,335 7/ 1949Tusson 241105 2,931,586 4/1960 Messing 241256 GERALD A. DOST, Primary Examiner US. Cl. X.R. 

